1. Field of the Invention
This invention relates to a device for heating plastics sections, in particular sections made of PVC, the device including a cabinet to accommodate a section, which cabinet has a supporting plate, side walls and a cover, as well as means for introducing hot air at one end of the section, so that it can flow past on the inside and outside of the section.
2. The Prior Art
Plastics sections are usually made by extrusion of PVC material. Certain applications require bending of the sections in order to obtain round forms, etc. Such processes are frequently employed in making doors and windows. The change in shape is achieved upon heating the section to a suitable temperature. For this purpose an oil bath may be applied, in which the section is heated to about 125.degree. C. Although the devices known in this context will permit rapid heating, considerable effort and expense is required for the subsequent cleaning work, when the oil has to be removed from the section. For this reason devices of this type are avoided if possible.
In DE-B 11 66 451 a device for heating plastics sections is described where hot air is blown into and passed along a section. Various air ducts and flow obstructions are utilized for preferred heating of special parts of the section. Such device is complex and demands a large input of energy.
U.S. Pat. No. 3,706,824 is concerned with a device for heating and bending lengths of pipe. In that case heating elements are introduced into the pipe in order to heat the pipe from inside. Such devices are not suitable for parts with more intricate cross-sections.
It is an object of this invention to overcome the above problems and to propose a device which will ensure rapid and efficient heating accompanied by simplicity of design and low cost.